“The first time I ever saw those square bales stacked up, I thought they looked like something that could be built with,” says John Kolk, owner of a straw bale home under construction near Picture Butte in southern Alberta. Little did Kolk know straw bale construction had been used successfully in Nebraska for nearly a century—and some Alberta homeowners were already turning to it as a perfect option in this dry climate.

Though the R-value of straw bales is somewhat disputed (claims range from R-20 to R-60 in an 18-inch thick wall and R-value can vary between different types of straw), the physical attributes of a straw bale (most often 14 inches high by 18 inches wide by three feet long) mean that there is a mass of insulation much thicker than a standard wood stud wall. This mass is said to perform exceptionally well, placing the type of home in the super-insulated category. A fiberglass-filled, conventional wood stud wall needs to be twice as thick as its standard to offer the same R-value of a straw bale wall (based on mid-range R-value estimates for straw bale walls).

A straw bale wall also offers the added benefit of being environmentally-friendly, considering a conventional wood-framed wall requires vast amounts of timber and a straw bale wall consists of just that—straw bales. At times wood is required such as around windows, doors and as a frame if the design requires it, but straw bale houses can be designed quite easily without a timber frame, with the bales and a layer of plaster on each side bearing the weight of the home.

Kolk followed up his interest with plenty of research in the ’90s, and then about five years ago he and his wife Laura decided to build a bale home on their acreage. He was interested in using larger straw bales for construction—choosing three-by-four-by-eight-foot bales for the job—enabling them to avoid a frame standard-sized bales would have required for that size of home. With the choice to use bigger bales, the material also allowed for deep window seats and upped the level of insulation considerably.

“Every time we were making a choice, it was for two or three reasons,” says Kolk. “We said, ‘Let’s be very deliberate about every choice we make, and look at the amount of space, the design, and the amount of materials we’re using.’ ”

The couple worked with Calgary designer Jorg Ostrowski of Autonomous & Sustainable Housing, who had designed, built and  now lives in his own home. He also has experience with principles the Kolks wanted to incorporate in their home, such as rainwater collection, alternative energy, passive solar design and a greywater system.

Joining the estimated 300 to 400 straw bale homeowners in Alberta, these types of homeowners are commonly attracted to straw bale building due to the “health” of the homes (an alternative for those with severe asthma or allergies aggravated by the synthetics in standard homes) and the sustainability of straw—a by-product of grain production.

Some build with bales, and some use pre-fabricated straw bale wall panels made in Saskatchewan by Green Planet Homes. Shawn Hayter, owner of Green Planet Homes, says these pre-fab panels make building faster, and the product less susceptible to moisture. Jason Whitfield (who started up the company under a different name) now builds ICF homes as well as any straw bale homes that come up through his company Stack-It Wall Systems Inc., claims that a home can go up in as little as two days and up to a couple of weeks for a larger two-storey home. These figures apply to the time the walls start to go up to lock-up stage. Because the panels consist of a stack of bales covered on either side by a layer of concrete stucco, the bales are protected from moisture throughout the building process.

For owner-builders, moisture during construction is one of the major concerns while erecting a straw bale house. Tests done by the Canada Mortgage and Housing Corporation (CMHC) over the past two decades on both test walls and standing homes show that if straw bale walls are properly protected from moisture—by elevating them from water drainage, providing proper drainage below, using appropriate stucco for the climate and sealing well around windows and doors—bale walls are not much more likely than wood-frame walls to rot.

“When they’re built well, they’re standing up quite well. They don’t seem to have major moisture problems,” says Don Fugler, senior researcher of housing technology with the CMHC, about the construction of straw bale homes. He explains that in a very rainy climate—the rain forest of the west coast for example—straw bale construction is not an appropriate option, but he contends wood is not either. “If a climate is so conducive to rot that most things are at risk, then (straw bale construction) is not a good idea.”

The other main issue owner-builders have to contend with is time. One of the most common complaints of straw bale homes is the project taking much longer than planned. This is caused not so much by the assembly of the stacked straw bale walls—which go up much like stacking blocks, in staggered rows—but more by the task of finding sub-contractors. Though sub-contractors generally do not charge more for work done on a straw bale home, it can sometimes be hard to find contractors willing to work with a new system, especially in a market where there is plenty of work.

To guard against these potential problems, aspiring straw bale homeowners may want to consider using a designer, builder or general contractor experienced in alternative building systems to guide their project. Any of these resources can provide links to crucial aspects of the building process such as an engineer’s stamp of approval, access to willing and qualified sub-contractors and the knowledge to properly guard the building against moisture.

And what of the mice, insects, marauding horses and fire? These myths make owners of straw bale homes chuckle. Walls sealed in concrete stucco are generally not susceptible to pests no matter what is behind the stucco—and if you have ever tried to burn a phone book, you have caught the gist of what it would be like to try to burn down a straw bale house. Bales, extremely short on oxygen, will smoulder for long periods of time but not burst into flame, unlike wood-frame houses whose walls encase vast expanses of air in which fire spreads quickly.

For urban construction, reducing the timeline is even more important as Whitfield points out, taking three years to complete a home in a new community is simply not an option.
He explains the main hurdle to overcome in building any alternative type of home within the city is getting an engineer’s stamp, something that can be done independently but, as previously mentioned, is made much easier through contact with a qualified builder or designer. NL

Interested in learning more about straw bale building? Check out:
• http://www.strawhomes.ca
• http://www.strawbale.com
• http://www.ecobuildnetwork.org/strawbale.htm
• http://www.strawbaleconstruction.net/
• http://www.greenplanethomes.ca
• More Straw Bale Building by Chris Magwood, Peter Mack and Tina Therrien
• The Airdrie Environmental Education Centre - a straw bale building completed in 2002